The glandular cyst is always, at first, multilocular; the tumor is made up of several cyst-cavities. As the tumor increases in size the pressure causes atrophy of intervening septa, so that two or more cavities are thrown into one, and the number of loculi becomes correspondingly diminished. As the cyst grows, therefore, the tendency is toward the unilocular form. Careful examination of a unilocular glandular cyst will usually reveal the remains of atrophied septa upon the walls. The epithelial _lining_ of these cysts is usually composed of columnar cells. In cavities of large size the cells are flattened by pressure, and in cavities of the largest size fatty degeneration and atrophy may have taken place, so that the lining cells entirely disappear. The cavities are often lined with a soft, velvety membrane, microscopically similar to mucous membrane. The columnar epithelium dips below the surface to form complex mucous glands. These glands may become obstructed, and secondary mucous retention-cysts are formed in the walls of the parent cyst. Such a mass of secondary cysts is often seen projecting into the main cyst-cavity or forming a lobulated prominence upon its outer surface. Follicular cystic degeneration, such as has already been described, may occur in the ovarian tissue of the wall of the glandular cyst, so that a secondary group of small cystic cavities may be formed. It is thus seen that the structure of an oöphoritic glandular cyst may be very complex. There may be one or more chief cyst-cavities, on the walls of which may be discovered the remains of septa which had formerly subdivided them. Projecting into the cavities may be seen honeycomb-like masses of secondary mucous retention-cysts; while in the walls of the tumor, perhaps rendering the surface lobulated, may be seen minor cyst-cavities formed by beginning glandular cystic degeneration or by simple cystic degeneration of ovarian follicles (Fig. 167). The _contents_ of a glandular cyst vary greatly, not only in different cysts, but in the different cavities of the same cyst. Pseudomucin, a peculiar _mucoid_ substance excreted from the lining gland cells, is a most important constituent of the contents of this cyst, and is almost characteristic. The fluid may be thin and colorless; it may resemble thick, tenacious mucus; it may be oily or syrupy in consistency; or it may resemble transparent jelly. It may be colorless, yellow, apple-green, or brown or black from the presence of decomposed blood. As a rule, the fluid becomes thinner as the cyst increases in size and age. The change is probably due to the alteration that takes place in the character of the lining membrane under the influence of continuously increasing pressure. The specific gravity of the fluid varies from 1010 to 1050.